1. Field of the Invention
The present invention relates generally to electrical connector or penetrator assemblies for connecting two cables or connecting a cable to electrical equipment, and is particularly concerned with a multiple layer conductor pin for incorporation in electrical or hybrid connectors or penetrators for subsea use or use in other harsh environments, and a method of manufacturing the multiple layer pin.
2. Related Art
Electrical connector or penetrator units include one or more conductors or conductor pins which extend through the units to carry current between opposite ends of the connector or penetrator connecting two cables or a cable and electrical equipment. Typically such conductors are surrounded by an insulating sleeve or have an outer insulating layer. In a typical electrical penetrator or feed through arrangement, a conductor pin extends through a bore in an insulating sleeve or body. In a typical electrical connector, plug and receptacle units or connector parts are each attached to cables or other devices intended to be joined by the connector to form completed circuits. One or more connector pins or probes extend through the plug unit and are designed for releasable mating engagement with one or more aligned sockets in the receptacle unit. In each case, the conductive pin is surrounded by suitable insulation along at least part of its length.
Partial discharge at higher AC voltages between conductor and insulator in typical connectors and penetrators is a long term reliability problem. In a connector/penetrator the insulation is typically formed by over molding the conductor or assembling an insulator sleeve or layer over the conductor. In both of these methods, it is not possible to completely eliminate the air void between conductor and insulator, and the air void is a source for partial discharge phenomenon. For example, there is a gap between the conductor and insulator when a pre-formed sleeve is engaged over the conductor. There is also difficulty in over molding a polymer insulation onto a metal substrate and achieving a consistently bonded interface. Typically, air voids are formed at the interface due to shrinkage of the polymer during processing and coefficient of thermal expansion differences between the materials. Since air is a poor insulator when compared with typical high voltage insulations, the electrical potential (voltage) will over-stress these air voids. As the air ionizes, the result is partial discharges. The resulting damage and ozone will eventually lead to a dielectric failure of the insulation.